1 Corinthians 9:19-21

For though I am free from all, I have made myself a servant to all, that I might win more of them. To the Jews I became as a Jew, in order to win Jews. To those under the law I became as one under the law (though not being myself under the law) that I might win those under the law. To those outside the law I became as one outside the law (not being outside the law of God but under the law of Christ) that I might win those outside the law.